Switch



Nov. 19, 1940. c J WERNER 2,222,209

SWITCH Filed Dec. 8, 1938 3 Sheets-Sheet l INVENTOR Cm. w/y J- WERNE/f Nov. 19, 1940. c. J. WERNER SWITCH Filed Dec. 8, 1938 3 Sheets-Sheet 2 W 0 (ll 0 Q M r M 9 7 m m w AMWS RE Y mm 0 m% w v n A N Nov. 19, 1940. c. J. WERNER SWITCH Filed Dec. 8, 1938 3 Sheets-Sheet I5 INVENTOR C FfLV/N J WE NE BY Q1 1,

ATTORNEYS Patented Nov. 19, 1940 UNITED STATES PATENT OFFICE SWITCH poration of Delaware Application December 8, 1938, Serial No. 244,552

15 Claims.

This invention relates to improvements in elec tric circuit control devices.

It is among the objects of the present invention to provide a control device which is adapted to be operated manually to close a circuit and which is automatically tripped to .open the circuit in response to overload conditions.

A further object of the present invention is'to provide a control device which has means rel quiring to be manually operated into one position from normal and then returned to the normal position to eifect closing ofthe electric circuit, said device having other means adapted automatically to effect opening of the circuit in re= sponsetoabnormal load conditions therein. A still further object of the present invention is to provide a control device, the actuator oi which, although apparently being operable in the usual manner, is rendered ineifective toclose the J circuit while an abnormal condition persists, the device, however, being rendered automatically capable of. closing=the circuit when said abnormal condition is terminated or removed.

Further objects and advantages of the present )invention will be apparent from the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the invention is shown.

In the drawings:

Fig. 1 is .a side view of the control device partly in section and partly in elevation, all of the ele ments thereof being shown in their normal position.

Fig.2 is a view similar to Fig. 1, the parts of the device, however, being shown in the initial operated position.

Fig. 3 is a fragmentary detail sectional view of one end of the housing.

Fig. 4 is a detail sectional view of the thermo- 40 static latch or detent.

Fig. 5 is a view similar to Fig. 1, the partsof the device, however, being shown in their final circuit closing positions. I Fig. 6 is a plan view of the device with the cover I plate removed.

Fig. 7 is a perspective view of the housing portion of the device.

Fig. 8 is a perspective viewof the over-center, spring actuated type circuit breaker. 2

50 Figs. 9, 10 and 11 are detail views of parts of.

the circuit breaker.

Referring to the drawings and more particularlv to Fig.7, the housing, made of any suitable molded, insulating condensation product such as 55 Bakelite or the like, is shown comprising a box-like structure having a bottom 20, side walls 2i and 22 and end walls 22 and 24. Cover plate 25, adapted to be placed on. the top, open side of the box-like housing, is secured in position by means of bolts 28 extending through openings 21.. it These openings 2? are provided in the parallel, inner walls 28 and 29. One end of each wall 28 and 29 terminates in the end wall 23 of the housing while the opposite ends of said walls 28 and 29 terminate short of and thus ,are spaced 10 from the end wall 26 of the housing. These two walls 28 and 29 are parallel with each other and with the side walls 241 and 22 of the housing. Being spaced from each other, walls 28 and 29 form a chamber therebetween for receiving certain elements of the circuit breaker, as will be described. A lateral groove 30 in the wall 28 provides one portion of away, the opposite portion of said way being provided with a corresponding lateral groove M in the'wall 29. These 20 lateral grooves are adjacent the ends of walls 28 and 29 spacedfrom the end wall 24 of the housing. Another lateral groove 32 in the wall 28, adjacent the recess 30, provides one portion of a way, the opposite portion of said way being pro- 1 vided by a corresponding groove 33 in the wall 39. Within the confines of the way provided by grooves 32 and M, a depression 36 is provided. in the bottom 20 of the housing while a similar depression is provided in said bottom 20 within 1 i the confines of the way provided by grooves 32 and 33. At the region designated by the numeral 31 the bottom of the housing is raised, this raised bottom together with adjacent sides of the walls 28 and 29 forming a receptacle for the thermostatic latch assembly, whichwill bedescribed later.

A groove 28 in the inner surface of the wall 28 provides one portion of a way and a corresponding groove 39 in the inner surface of wall 29 provides the other portion of a way for receiving a flange 98 provided on the thermostatic latch to hold said latch in proper position within the housing.

The end wall 23 is thicker than the end wall 24, as shown in Fig. i. This end wall 23 has a. rectangular shaped recess 42 in its outer surface, said recess extending from the top edge of wall 23 substantially half way down to the bottom surface or edge. A narrower recess ll communicates with the bottom of the recess 40 and K terminates short of the bottom surface of the housing. This recess 4! is under-cut, forming an interior groove 42. Within the confines of the recess 40 the end wall 23 is cut away as at 43, providing communication between the said recess 40 and the space between walls 28 and 29, thereby permitting the thermostatic latch, adapted to be received by said space, to extend through the end wall into the recess 40, as will be described. On each side of the recess 40 another recess 50 and 5| respectively is provided in end wall 23, one end of each recess 50 and 5| terminating in the upper edge surface of the housing, the other just short of the bottom surface of the housing. Recesses 50 and 5| are each under-cut to provide an internal groove, the groove in recess 500 being designated by the numeral 52, the groove in recess 5| being designated by the numeral 53. These grooves 52 and 53 form ways for receiving the heads of terminals to be described. I

The housing described'in the aforegoing paragraphs is, as has been mentioned, preformed from any suitable insulating, condensation product such as Bakelite or the like, the various grooves, recesses, ways and chambers forming receptacles into which certain elements of the circuit breaker are easily inserted, as will be described.

The end wall 23 of the housing has been described as having recesses 50 and II for receiving terminals. These recesses are each provided with under-cuts forming grooves. In Fig. 3 a sectional view taken through recess 5| and the terminals received thereby is clearly shown. The under-cut is shown providing the groove 53. The terminal has an enlarged head portion 6| whose thickness is equivalent to the width of groove 53, the width of the head 8| being slightly less than the width of the under-cut groove 53. The screw-threaded shank portion of the terminal 80 extends through the opening of the recess 5|. An insulating plate 82 is placed on the outer surface of end wall 23, this plate having an opening through which the threaded shank of the terminal extends. The stationary contact member of the circuit breaker, which member comprises relatively angular portions 83 and 84, is held so that the portion 83 rests upon and against the insulating plate 02, this contact portion being perforated to fit over the screwthreaded shank of the terminal 80. The other angular portion 94 of said contact member extends along the upper surface of the housing and over the space provided between the inner wall 29 and the outer side wall 2| of the hous-- ing, as is clearly shown in the Fig. 6. Wrapped around the terminal 30 and engaging the contact 63 is a wire 85' which is one end of the heating unit of the thermostatic latch, to be detailedly described hereinafter. A nut 83 on the threaded stud of terminal 60 clamps the wire 95, contact 83 and insulating plate 82 toward-the outer surface of the end wall 23 of the housing while the head portion 8| of said terminal is drawn against the inner side walls of the groove 53 in recess 5|. Thus it may clearly be seen that the contact 83 is tightly clamped into position on the housing. A stud similar to the terminal 80 is provided on the bottom end of recess 5|, this stud being designated by the numeral 10 having a head 1| fitting in the recess 5| and being provided with a nut I2 which urges a washer 13 into clamping engagement with the outer surface of the insulating plate 62, holding it securely in position.

A similar terminal stud designated by the numeral I5 is received by the recess 4|, this terminal stud also having a head 16 fitting into the groove formed by the under-cuts 42 in the recess 4|. This stud has the other end 11 of the heating coil of the thermostatic latch wound about it, the nut 18 on said stud 15 clamping it tightly against a washer 19 provided between the end of the wire TI and the insulating plate 82. The other stationary contact 83 of the circuit breaker corresponds exactly to the .stationary contact 63, this stationary contact 83 having a portion 84 extending over the space provided between the inner wall 28 and the outer wall 22 of the housing. Inasmuch as the construction of this stationary contact and its method of being secured to the housing of the device is identical with contact 63, no further description thereof will be made.

The thermostatic latch of the circuit breaker is clearly illustrated in Figs. 1, 2, 4, 5 and 6. The thermostatic 'latch comprises a body portion hollowed out as at 9| for receiving a heating coil 92. One end of this body portion is reduced in diameter as at 93, providing a bearing for supporting the ratchet wheel 94, said ratchet wheel being provided with teeth formed in its outer peripheral surface. The end of the body portion as at 96, is enlarged to prevent removal of the ratchet wheel. A body of solder 91 secures the ratchet wheel 94 to the body 90 so that normally said ratchet wheel cannot rotate relatively to said body. This solder, however, is of such a character that when the heating coil within the body 90 attains a predetermined temperature and consequently heats up said body to a predetermined temperature, it will be softened sufficiently to release the ratchet wheel and permit it to turn relatively to said body. Flange 98 is provided on the body, opposite sides I of this flange being received by the ways formed by grooves 38 and 39 in the inner walls 28 and 29 respectively, so that when this thermostatic latch has its flange 98 inserted in said grooves 38 and 39 respectively and the latch rests upon the bottom 31 this latch will be properly located in the housing. A small piece of insulating material 99 is placed in the way provided by grooves 38-39 so as to be interposed between the latch body 90 and the cover plate 25, whereby said latch is held against movement after the control device is assembled.

The circuit breaker in the present instance is of the over-center, spring actuated type. Figs; 8 to 11 inclusive clearly show its detailed construction, while Figs. 1, 2, 5 and 6 illustrate it assembled within the housing.

This over-center, spring actuated circuit breaker comprises an actuator I00, made of any suitable insulating material and having a portion |0| which is slidably received and reciprocably fits in the ways provided by the oppositely disposed grooves 30 and 3| in the inner walls 28 and 29 respectively. An extension |02 at the one end of said actuator provides an anchorage for a spring I03, (see Figs. 1, 2 and 5) the other end of this spring seating in the recess 34 formed in the bottom 20 of the housing. A projecting shelf I05 extends from the side of said actuator more adjacent the thermostatic latch when the actuator is assembled in its proper position within the housing. On the directly opposite side, said actuator has a transverse V-shaped groove |06 providing the fulcrum for the tiltable contact member I01. As shown in Fig. l, shelf I05 engages cover plate 25, thereby limiting the movement of said actuator by spring I03. The remain- .ing portion beyond said shelf extends through an opening in the cover plate and may be termed the the V-shaped slot I06 and the side having the shelf I05. This slot has its one end adjacent the shelf, the other end terminating adjacent the bot tom of the rectangular portion IOI.

In Figs. 6 and 8 a clear showing of the mov able contact is made. This tiltable or movable contact comprises two parallel contact arm poi"= tions H0 and III formed integral with a cross member I09. Each end of contact arm portions H0 and III is provided with a contact member H2 and H3 respectively. The cross member- I09 has a split, inwardly extending portion forming two inwardly extending arms H5 and H16 (see Fig. 6). The ends of these inwardly extending arms H5 and H6 plvotally engage the V-shaped slot I06 in the actuator portion IN on the respective sides of the longitudinal slot I00 in said actuator. These arms are yieldably urged into pivotal engagement with the bottom of said V-= shaped slot by a spring I20, one end of which is anchored to the cross member I09 as at IN. The opposite end of this spring is hooked in the eye I22'of the plate I23 shown in Figs. 6 and 9. This plate has oppositely disposed extensions I26 forming a head thereon. The plate I23 projects through opening I25 in the anchor-plate i26 so that the oppositely disposed extensions 824 on said plate engage the outer surface of said anchor plate. This anchor-plate I26 is adapted to be reciprocated against one edge in the way formed by the oppositely disposed grooves 32 and 33 in the inner walls 20 and 29. The spring I20 extends through the slot I00 in the actuator as is shown in Fig. 2, and inasmuch as this spring is anchored between the tiltable contact portion I09 and the plate I23 it will urge the anchor-plate I26 against the one edge of the way formed by grooves 32 and 33 and will likewise urge the tiltable contact portion I09 and more particularly the inwardly extending arms H5 and H6 thereof into pivotal engagement with the V-shaped groove I06 in the actuator I00. The anchorplate I26 has a part- I30 which extends into one end of a coil spring I3I the opposite end of said coil spring resting in the recess 35 provided in the bottom 20 of the housing. This spring yieldably urged this anchor-plate upwardly so that it normally engages with the bottom surface or the shelf I05 as shown in Fig. 1. Plate I26 has a portion I35 extending at right angles therefrom, this portion in turn having an angular tongue I36 adapted lockingly to engage with the teeth 95 of the ratchet wheel 94 when the ac tuator. I00 is depressed from its normal position shown in Fig. lto its operated position shown in Fig. 2. In this Fig. 2 the tongue I36 of the plate I26 is shown in such ratchet wheel engagement. Naturally when the actuator is released and per-= mitted to return from the position shown in Fig. 2, to the normal position shown in Fig. 1, the anchor-plate I26 will be retained in the depressed position as is shown in Fig. 5. The spring I3i, however, is at all times tending to urge said plate I26 into the position as shown in Fig. 1, but said plate I26 being locked in this depressed position, by engaging the non-rotatable ratchet wheel 94, is thus prevented from returning to this normal position until such a time as the heating coil 92 within the thermostatic latch member will heat the body of said latch member sufliciently to melt the solder 91 which securely holds the ratchet wheel to the main body portion 90 of the thermostatic latch. When the solder 91 is melted, the ratchet wheel may rotate, thereby releasing the tongue I36 of the anchor plate I26 and consequently permitting the spring I3I to flip the plate 626 to its upper, normal position as shown in Fig. i.

It will be seen that when all parts of the circuit breaker are in normal position as shown in Fig. l, the anchorage points of the spring I20 on the portion iii of the tiltabie contact and the plate B23 respectively, are above the horizontal plane passing through the point of pivotal engagement between the arms H5 and N6 of said tiltable contact member I01 and the bottom of the V-shaped groove I|06 in the actuator I00. Therefore the force exerted by the spring I20 upon the tiltable contact member I01 and par into its operated position as shown in Fig. 2,

against the eifect of spring I03, the fulcrum point of the tiltable contact is still held beneath the level of the anchorage point of spring I20 on the tiltable contact I017 and thus during this depressing of the actuator the tiltable contact is maintained in its normal position in which it engages the bottom of the housing. As the actu- I ator is depressed the anchor-plate I26 is also depressed for, as has been mentioned heretofore, it normally is urged into engagement with the bottom of the shelf I05 of the actuator by its spring i3i. As the anchor-plate I26 is moved into its operated position as shown in Fig. 2 by the actuator, its tongue I36 will lockingly engage the teeth of the ratchet wheel 94, such locking engagement retaining the anchor-plate I26 in this actuated position inasmuch as the ratchet wheel 94 cannot normally rotate relatively to the main body portion of the thermostatic latch. Even when the parts are in position as shown in Fig. 2, the anchorage points of spring I20 on the portion I09 of the tilting contact and the plate in are still above the horizontal plane passing through the fulcrum point of said tiltable contact, or more particularly the bottom of the V-shaped groove I06 on the actuator I00, thus the tiltable contact is still urged against the bottom 20 of the housing and out of engagement with its cooperating stationary contacts. This condition will prevail until the operator releases the actuator I00, permitting its spring I03 to return said actuator to its normal position as shown in Fig. 5.- In this Fig. 5 it is clearly shown that when the actuator I00 is returned to its normal position while the anchor-plate B26 is retained by the ratchet wheel 94, relative position between the fulcrum point of the tiltable contact and the anchorage points of the spring I20 will be altered. Under these circumstances the anchorage points of spring I20 with the tilting contact HI and the plate I23 will be below the horizontalplane passing through the pivotal point of the tiltable contact or particularly the bottom of the V-shaped groove I06 in the actuator, and consequently the spring I20 will exert a force on the tilting contact member, urging it counter-clockwise so that its two contact arms I I0 and I I I will be moved upwardly away from the bottom 20 of the housing, causing contacts H2 and II! to en gage their respective stationary contacts 64 and 84. Naturally when the actuator is again depressed into the position as shown in Fig. 2, the anchorage points of spring I20 will be brought below the pivotal point of the tiltable contact member and the contacts H2 and II 3 will again be moved out of engagement with their respective stationary contacts. For this it may be seen that the actuator I00 must be released and permitted to return to its normal position to cause contact engagement and circuit closing while the anchorplate I26 is in locking engagement with the ratchet wheel 94 of the thermostatic latch.

As has previously been stated, an overload or abnormal current condition flowing through the heating coil 92 of the circuit breaker, which coil is connected in the main circuit, will cause a heating up of the body portion of the thermostatic latch and when a sufllciently high temperature has been reached, the solder 91, securing the ratchet wheel to the body 90, will be softened sufficiently to release said wheel. This permits the spring I3I of the anchorage-plate I26 to become effective quickly to move said actuating plate upwardly so that its upper edge again engages the bottom surface of the shelf I05 on the actuator I00. When this occurs the anchorage point of spring I20 on the plate I23, which plate forms an assembled part of the anchor-plate I26 is quickly thrust upwardly above the bottom of the V-shaped groove I06 in the actuator, which is the pivotal point of the movable contact member, thus again bringing both anchorage points of this spring I20 on the upper side of said pivotal point wherebylspring I20 will exert a force upon the tilting contact I09 to move it clockwise about its fulcrum point, consequently quickly shifting the contacts H2 and II: out of engagement with their respective stationary contacts 64 and 84 and thereby breaking the circuit. From this it will.be seen that this anchor-plate I26 now acts independently as an actuator for the tiltable contact I 09, being released by the thermostatic latch when said latch is heated to a predetermined temperature in response to a predetermined current flowing through the circuit under abnormal conditions.

As long as such an abnormality persists, the high current flow through the heating coil 92 will soften the solder 91 to permit rotation of the ratchet wheel 94 under which condition said ratchet wheel cannot retain the plate I26. Thus contact engagement between contacts H2 and H3 and their corresponding stationary contacts 64 and 84 cannot be completed, for to cause contact engagement relative movement between the actuator I00 and plate I26 must take place and the plate I26 must be retained by the ratchet wheel 94 to provide for such relative movement. However, if the abnormality is removed then the heating coil 82 will not become sufllciently hot to cause a melting of the solder 91 whereby ratchet wheel 94 will again be secured to the body portion 90 of the thermostatic latch. Under these conditions depression of the actuator I00 will again move tongue I36 of the anchor-plate I26 into locking engagement with the ratchet wheel 95 which, inasmuch as it cannot turn, will retain said anchor-plate in its operated position.

From the aforegoing it may be seen that applicant has provided a circuit control having a spring actuated circuit breaker, a reciprocating actuator and cooperating anchor-plate, which anchor-plate must be retained in one position to permit the actuator to move the contacts into engagement and which actuator-plate when released, itself becomes an actuator for moving the tiltable contact quickly out of engagement with its stationary contact under abnormal conditions in the circuit to which the circuit closing device is connected.

The housing is preformed and provides receptacles into which various assemblies such as the over-center, spring actuated type circuit breaker, the actuator and its cooperating anchorplate, actuator and the thermostatic latch may easily be assembled and consequently may just as easily be withdrawn for purposes of inspection or repair.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be provided, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. A circuit control comprising in combination, a circuit make and break device, a snap spring for said device, reciprocative actuators for said device, one providing a pivot for the device the other an anchorage for the snap spring, said actuators being adapted to move in unison and maintain the device in circuit breaking position, the said one actuator being adapted to actuate said device to make or break the circuit when moving relatively to said other actuator, said other actuator being adapted to actuate the device to break the circuit when moving relatively to said one actuator, and means releasably holding the said other actuator to effect relative movement between said actuators.

2. A switch, comprising in combination, a support providing substantially parallel ways, a fixed contact on said support; a tilting contact arm, a fulcrum block for said arm; an anchorplate, both said block and plate being reciprocatively mounted in the ways of the support, the block having provisions for moving the plate out of its normal position in one direction, springs yieldably urging the block and plate in the opposite direction, a snap spring interposed between the contact arm and anchor plate and adapted to maintain the tiltable contact arm out, of engagement with the fixed contact while the anchor plate is in its normal position or is moving with the fulcrum block, and means for releasably retaining the anchor-plate out of its normal position whereby movement of the fulcrum block relatively to the plate into its normal position will effect engagement of the contacts.

3. A switch, comprising in combination, a support providing adjacent, parallel ways, a fixed contact on said support; a movable contact member; an anchor-plate slidably supported in one of said ways; an actuator reciprocatively supported in the other of said ways, said actuator having a notch in which a portion of the movable contact arm pivots and having means engaging the anchor-plate to move out of normal position in one direction; springs urging both the actuator and anchor-plate into normal position; a tension spring anchored at one end to the movable contact and at the other to the anchor plate, said points of spring anchorage being on the side of the fulcrum of the movable contact more adjacent the fixed contact when the actuator and anchor-plate are in normal position or while said actuator and anchor-plate move in unison, whereby said tension spring urges the movable contact away from the fixed 7 contact; and a thermostatic latch adapted releasably to retain the anchor-plate in an operated position to permit movement of the actuator relatively to the anchor plate whereby to shift the anchorage point of the tension spring with the anchor plate to the side of the fulcrum of the movable contact more remote from the fixed contact thereby to cause said tension spring quickly to tilt the movable contact into engagement with the fixed contact when the actuator is returned to is normal position.

i. A switch comprising in combination, a housing, a fixed contact on said housing; a tiltable contact member; a spring-loaded reciprocatable block providing ashiftable fulcrum for said tiltable contact member; a snap spring anchored at one end to said contact member; a spring-loaded reciprocatable anchor-plate adapted to be moved out of normal position by the block, said plate having the other end of the said snap-spring secured thereto and providing a shiftable anchorage for said end of the spring; and a thermostatic latch adapted to engage and retain the anchor-plate in the depressed position whereby return movement of the block relatively to the fixed anchor plate will cause a change in the relative positions of the fulcrum of the movable contact member and-the snap-spring anchorage on the plate, quickly to snap the movable contact into engagement with the fixed contact.

5. Switch mechanism comprising a switch member movable to open and closed positions, a reciprocatable pivot block for said member; a snap-spring for operating said member; an anchor-plate for one end of said spring, said anchor plate being reciprocatable with said pivot block to maintain relative positions between the anchorage points of the snap-spring and the switch pivot whereby said snap-sprin maintains the switch member open; and a latch adapted to engage and retain the anchor-plate in one position whereby movement of the pivot block reverses the relative position of the snap-spring an.- chor points and the switch pivot, to cause the snap-spring to actuate the movable switch memher to closed position.

6. Switch mechanism comprising a switch member movable to engage and disengage a fixed contact; a reciprocating block providing a pivotal support for said switch member; a sliding anchor-plate adapted to be moved from normal into its operated position by said block; springs urging the block and anchor-plate into normal position; a snap spring secured between the switch member and anchor plate so that normally the pivot point of saidmember is, on the side of the snap-spring opposite the fixed contact,

said snap-spring constantly holding the switch member out of engagement with the fixed contact as thepivot block and anchor-plate are reciprocated; and a latch adapted releasably to retain the anchor plate in its operated position thus permitting relative movement between the pivot block and anchor plate and shifting the pivot point of the switch member on' the side of the snap spring adjacent thefixed contact to cause the switch member to shift.

'7. A circuit controller comprising in combination, an over-center, spring actuated circuit make and break device; two reciprocative actuators for said device adapted to maintain the device in circuit breaking position while reciprocating in unison and adapted to actuate the device to make or break the circuit when one of said actuators moves relatively to the other; and a temperature relatively thereto to actuate said device for mak-' ing and breaking the circuit; the said one of said actuators, when released by the latch, moving the said device to break the circuit.

8. A circuit controller comprising in combination, an over-center spring actuated circuit make and break device; two spring loaded reciprocative actuators, one being adapted to actuate the other against the effect of its spring, said actuators when moving in unison maintaining the said device in circuit breaking position, and when moving relatively to each other one of said actuators is adapted to move said device to break the circuit, the other actuator to move said device to make and break the circuit; and a temperature controlled latch adapted releasably to engage and retain the said one actuator in its one extreme position to permit the other actuator to move relatively thereto.

9. Switch mechanism comprising a switch member movable to engage and disengage a fixed contact, a reciprocating actuator providing a pivot for said switch member; an anchor plate adapted to be actuated out of normal position by said actuator and in a plane substantially parallel thereto; springs urging the actuator and anchor plate into normal position; a snap spring secured between the switch member and anchor-plate and adapted to urge said switch member out of engagement with the fixed contact while the actuator and anchor block are in normal positions relativel to each other; and a latch adapted re" leasably to retain the anchor plate when it is actuated out of normal position whereby the return of the actuator to normal position and away from the anchor-plate renders the snap spring efi'ective to shift the switch member into engagement with the fixed contact.

10. Switch mechanism comprising a switch member movable into circuit opening and closing positions; a spring for actuating said member; a reciprocative element providing a shiftable anchorage for one end of said spring; a reciprocative actuator adapted to be engaged by said element and to operate it in one direction, said actuator providing a pivot for the switch member on one side of the axis of the spring while the actuator engages the element whereby said spring will maintain the switch member in circuit-opening position; springs urging the actuator into normal position and the element against the actuator; and a releasable latch for retaining the element at the limit of its movement in said one direction to effect shifting f the pivot of the switch member to the other side of the axis of its spring upon the return of the actuator to normal position thereby causing said spring to shift said member into circuit-closing position.

11. A. trip-free over-center, spring actuated switch comprising in combination a stationary contact, a movable contact, a reciprocative block providin a shiftable fulcrum for said movable contact; a spring urging said fulcrum block into normal position; an anchor plate engageable by the block and adapted to be translated from nor mal into operative position by said block through a path substantially parallel to the reciprocative movement of said block; a spring urging the anchor plate into normal position; a contact actuating spring interposed between the movable contact and the anchor plate, said spring being effective to maintain the contacts disengaged when the anchor plate is in normal position and also While it is being moved out of normal position by the block, said spring, however, becoming effective to cause contact engagement when the block is returned to normal position while the anchor plate is maintained in its operative position; and a latch, thermostatically controlled, for retaining the anchor plate in operative position at predetermined temperatures thereof.

12. A circuit controller comprising in combination, a circuit make and break device; a releasable detent; reciprocative actuators for said device, one being adapted to be moved by the other in one direction to engage the detent, relative movement of said other to said one actuator in the opposite direction, eflecting circuit closing by the device, release of said one actuator by the detent efi'ecting circuit opening by the device.

13. A circuit controller comprising in combination, a circuit make and break device; a releasable detent; actuators for said device, movable in unison in one direction to effect engagement of the one actuator with the detent while maintaining the device in circuit breaking position, movement of the free actuator ,in the other direction and relatively to the detained one, eflecting cir-' cuit closing by the device; said one actuator, when released by the detent, moving the device to circult breaking position.

14. A circuit controller comprising in combination, a circuit make and break device; a releasable detent; two reciprocative members, one adapted to move the other into locking engagement with the detent while maintaining the device in circuit breaking position, said one member being movable relatively to the detained one to actuate the device to make and break the circuit without releasing the detent, said other member, when released, moving the device to open the circuit regardless of the position of the said one member.

15. A circuit controller comprising in combination, an over-center spring actuated circuit make and break device; a thermostatic detent; two reciprocating members, one actuated by the other into locking engagement with said detent while maintaining the circuit device open, said other member when released eflecting operation of the device into circuit closing position, the detained member when released by the detent efl'ecting operation of the device to open the cira cult.

CALVIN J. WERNER. 

